Thread: 85 6.2 diesel decision

I'm trying to decide if I should buy a pickup. It's an 85 GMC three quater ton 6.2 liter diesel. It has 140,000 miles, automatic, 4x4. It's a really nice truck prety good paint strait body nice wheels and needs new tires, plus verry nice sterio. But I've been told that diesel's are just big piles but this is a really nice truck. What do you think? It's my first truck and a dont want to mess up with this one. I will be going 4 wheeling, hauling a horse around, going to work and going to school. Maby somebody can give me some imput on the diesels. Thanks.

I know a friend of the family with a 1984 Suburban with the 6.2L diesel and its great...nice for the few canoe trips I have been on with them in Missouri that 4wd sees some use....on the other hand I hear lots of other stuff about them that worry me including the fact that they use the same block as a gas engine on the 6.2L...meaning that it seems a bit risky to be running a diesel engine which has such high combustion pressures in a block made for gas combustion...dunno...still sounds nice though...I can almost kick myself right now because I passed up an 84 that sounds similar...just take a look around and use some instinct on where this vehicle has possibly been...you dont want to end up with the neighbors daily Mudder...best of luck

Ok lets put that rumor to rest. the 6.2 and 6.5 are diesel engines, not gas conversions. Look into the facts before you talk out of turn. Actually the 6.9 IH was originally a gas engine, but it worked ok for them. The gm diesel that was a gas conversion was the 5.7 olds engine.
With that year truck with the auto, is it the 700r4 or the TH 400. If its the 700r4 look to have a rebuild done before to long. If its the th 400 it will be much stouter and will mena you have the higher torque rated engine.
The 6.2 are good engines, if you do buy it, get a membership to the 62-65 diesel page.
Dino

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I am not the biggest and I am not the best but I fall somewhere comfortably in between.

Sounds like a nice truck! I'd buy it in a second! Add a Banks turbo and you will be smokin' newer trucks! Go for it! Some 6.2's were good, some were problematic, a subscription to the http://www.thedieselpage.com is a must if you buy this truck.

OK, I have been a 6.2 fan ever since they came out. I worked on a ton of them in the military, and I have studied, rebuilt, modified and played with them for years.

The next person that tells you that the 6.2 has the same block as a gas engine, call them an idiot and question if their parents were related BEFORE they were married. Anyone who has ever made this statement has never seen a bare gasser block and a bare 6.2 block side by side.

So where did this rumor come from? Well, in the 70's, GM produced a diesel based on the Olds 350. Now, there is a difference between "based on a gasser" and "converted to a gasser." The Olds diesel was BASED ON the gas motor, but was not a gasser converted to a diesel. Before anyone disputes this, look at an Olds diesel block next to an Olds gas block (better yet, weigh them). There is alot of extra metal in the diesel block. However, it shared alot with the gasser- dimensions for one thing. It is easily possible to convert an Olds diesel to a gasser.

Now, GM had terrible luck with this Olds diesel- mostly because America wasn't ready to accept diesels, but alot had to do with it's gas motor roots and a company inexperienced with diesels. But with a little work, these diesels still make "decent" motors.

On to the 6.2... This is not the same engine as the Olds, and DEFINATELY not the same as a gasser. The 6.2 has its quirks, but so does any other motor out there. I love these 6.2's and the 6.5's. They are powerful, reliable, and fairly cheap to repair/upkeep.

I think if you are going to be pulling horses around, you will be very happy with a diesel. They do well off road too, but keep in mind, you don't want to unwind these engines like you do a gasser. Diesels can make twice the torque at half the RPM's- they are monsters in the low to mid RPM range. But if you have a habit of winding a motor to 8 grand very much, you won't like the results.

Simple rule to follow- if you like reving the motor and acting like a race car, go with the gasser. If you like alot of pulling power and decent mileage and dependability, the diesel is your ticket. I'd say go for it- only you will know if you will like it. If not, it wouldn't be hard to sell.

Psyclopse,my uncle has an 84 6.2 diesel K30,I plowed with it for 5 years.it has a 4 spd manual SM465,and 4.10 gears.I dont know what you consider to be powerful,or torquey,but trust me this and other 6.2's i ve driven cant even getout of there own way.The 1 ton is downright dangerously slow when ther blade is on and V-box is full.As far as rev it out-you must wind it right to the max in order for it to pull the next gear,even on flat ground.I am guessing,but id say a 4.3 v6 would flat smoke this thing in the same truck,while turninmg less RPM's.In a 1/2 ton or 3.4 pickup,maybe the perfromance would just be poor,mbut thats not good enough for me.The 6.2 has been a great engine for him,its tired now,it has 65K farm truck/plow truck miles on it(probably 8000 hrs+),since it is always left runningthroughout storms,even overnight.In 93 it ran for 5 weeks straight during the cold snap we had,he just added 2 qts of oil a week to be safe.Reliable-yes-powerful-torquey-never

Are you saying that (for instance) from a dead-stop take off, the truck will wind up (RPM-wise) before it shifts into the next gear? That's what I got from (the middle) of your post, but maybe I am not understanding right.

At any rate, I bought my 88 GMC 3500 last spring. It was purchased new by an older local gentleman who only used it a few times a year to pull his boat to the reservoir. When he sold it to me, the thing had only 55k original miles on the whole truck. Believe me, you just don't see an 88 GM truck around here with the cab corners still solid. This truck was pampered.

At any rate, when I got the truck, it would really rev up pretty high before it would shift. I had complained about it alot, but always had too much going on to mess with it. I lent it to a buddy (who works at a GM dealership) to move with, and he adjusted the cable that controls the shifting. Now it shifts like a normal truck. This could be what is happening to the 84 you mentioned.

I don't know, my experiences with this moter have been positive. My diesel will plain out-push and out-pull any of the gassers I had lately (however, acceleration is NOT a strong point). I have been happy with the power of these engines. I know some of the other diesels (Cummins, PowerStroke) are alot more powerful, but heck, the 6.2 is easier on the wallet to repair.

I still stick to my opinion for this thread- buy the truck if it is in good shape. If you don't like it you can 1) sell/trade it for a gas truck or 2) put a gas motor in it.

If the price is right and it appears to have been maintained properly, I'd say go for it! I had been looking for a nice diesel PU under $6000 for years. I recently purchased a clean 83 Chevy G20 conversion van with a NA 6.2 diesel, 106,000 miles for about $3000. I absolutely LOVE it! Even with a 4.10 rear end, I'm getting around 20 MPG on the highway. It has terrific acceleration and will easily "keep up with traffic". Ownership has been less scarry since I joined The Diesel Page. http://www.62-65-dieselpage.com/ Tons of tips, info, troubleshooting, etc. Membership is about $20 /yr and is way worth it (I've probably saved 5 times that already in repairs / troubleshooting).

I haven't joined The Diesel Page for the simple reason that the pay-for-membership websites are out of style. That's just not what the net should be about. Once, I had considered joining- they had enough free info to give you an idea as to what may be inside. Now, there is next to nothing for free there- you would have no idea if you were paying for crap or not. And if you weren't satisfied, I doubt they'd refund your money.

I posted a simple question on their board once- I asked where I could get info or a wiring diagram. I was pretty much told that my post was out of line and I'd have to be a member to get info like that. Then, the thread disappeared. Yea, that made me want to join. Besides, what I hear, most of the really good info comes from the message board there- so I have to pay to see someone's advice- someone who also had to pay- the owners are making money from the work of others.

I'm sorry, I can go to Chuck's Chevy Pages and get a ton of info for free. I don't know if he has a membership there, but there is enough free info to keep you busy for weeks- you'd know what a membership would get you. As far as diesel-only sites go, I'd like to see http://www.gm-diesel.com/ flourish instead- it's free. They have the drive, they just need the visitors and people to contribute their knowledge. Also, The Diesel Page didn't want to trade links with them because they didn't want the competition- especially from a free site.

I kind of agree with your view on a free internet, however its just not possible. Jim Bigley, owner of the diesel page, is not getting rich on this. Yes he is making money, but it takes money to get money. His expenses are immense. is $15.95 too much to spend for a wealth of info? 4.3 cents a day!!!! If thats money to burn, then I must be a billionaire!! I dont think its out of style. No, your not paying for crap there. Diesel Page members are a very tight knit group (close to 6000 members) that actually meet at a yearly get together. Their forum is a wealth of knowledge and has helped many. Where does the knowledge from this site come from??...US

I tend to get upset when someone spouts off negatively about something that they have not tried. No one is pulling your arms off asking you to join. Its just that when you are asking diesel related questions in here (that may or may not be answered correctly), in the DP you have a much broader base of "experts" to help you out.

Believe me, if there was something negative to being a DP member, your negative views of the DP might be supported by others here.